我是Android开发的新手，并决定在xamarin android中创建一个tabLayout。我把它全部搞定了，但唯一的问题是;我的ViewPager显示的是xml Layouts而不是片段。
我现在无法使用布局内的按钮做任何事情，我已尝试使用适配器等不同的东西，但似乎无法使其正常工作。
TabLayout是自定义的，包含LinearLayout和HorizontalScrollView。
我的MainActivity添加了整个tabLayout：
public class MainActivity : Activity
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
// Api getapi = new Api();
// getapi.GetApi();
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
FragmentTransaction transaction = FragmentManager.BeginTransaction();
SlidingTabsFragment fragment = new SlidingTabsFragment();
transaction.Replace(Resource.Id.sample_content_fragment, fragment);
transaction.Commit();
}
}
我的片段与适配器和ViewPager（只是夸大布局丑陋的atm）：
public class SlidingTabsFragment : Fragment
{
private SlidingTabScrollView mSlidingTabScrollView;
private ViewPager mViewPager;
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
var view = inflater.Inflate(Resource.Layout.fragment_sample, container, false);
return view;
}
public override void OnViewCreated(View view, Bundle savedInstanceState)
{
mSlidingTabScrollView = view.FindViewById<SlidingTabScrollView>(Resource.Id.sliding_tabs);
mViewPager = view.FindViewById<ViewPager>(Resource.Id.viewpager);
mViewPager.Adapter = new SamplePagerAdapter();
mSlidingTabScrollView.ViewPager = mViewPager;
}
public class SamplePagerAdapter : PagerAdapter
{
List<string> items = new List<string>();
public SamplePagerAdapter()
: base()
{
items.Add("Home");
items.Add("Surfboard kopen");
items.Add("Surfboard customize");
items.Add("Nieuwsbrief");
items.Add("Contact");
items.Add("FAQ");
}
public override int Count
{
get { return items.Count; }
}
public override bool IsViewFromObject(View view, Java.Lang.Object obj)
{
return view == obj;
}
public override Java.Lang.Object InstantiateItem(ViewGroup container, int position)
{
if (position == 4)
{
View view = LayoutInflater.From(container.Context).Inflate(Resource.Layout.Contact, container, false);
container.AddView(view);
return view;
}
if (position == 0)
{
View view = LayoutInflater.From(container.Context).Inflate(Resource.Layout.Home, container, false);
container.AddView(view);
return view;
}
}
public string GetHeaderTitle(int position)
{
return items[position];
}
public override void DestroyItem(ViewGroup container, int position, Java.Lang.Object obj)
{
container.RemoveView((View)obj);
}
}
}
Main.axml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#E2E2E2"
android:id="@+id/sample_main_layout">
<FrameLayout
android:id="@+id/sample_content_fragment"
android:layout_weight="2"
android:layout_width="match_parent"
android:layout_height="0px" />
</LinearLayout>
fragment_sample.axml：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ffffff">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/backgroundd"
android:src="@drawable/SurfChicks"
android:scaleType="centerCrop"
android:alpha="0.35" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<Smoothboard_Stylers_App.SlidingTabScrollView
android:id="@+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1" />
</LinearLayout>
</RelativeLayout>
Scrollview：
namespace Smoothboard_Stylers_App
{
public class SlidingTabScrollView : HorizontalScrollView
{
private const int TITLE_OFFSET_DIPS = 24;
private const int TAB_VIEW_PADDING_DIPS = 16;
private const int TAB_VIEW_TEXT_SIZE_SP = 12;
private int mTitleOffset;
private int mTabViewLayoutID;
private int mTabViewTextViewID;
private ViewPager mViewPager;
private ViewPager.IOnPageChangeListener mViewPagerPageChangeListener;
private static SlidingTabStrip mTabStrip;
private int mScrollState;
public interface TabColorizer
{
int GetIndicatorColor(int position);
int GetDividerColor(int position);
}
public SlidingTabScrollView(Context context) : this(context, null) { }
public SlidingTabScrollView(Context context, IAttributeSet attrs) : this(context, attrs, 0) { }
public SlidingTabScrollView(Context context, IAttributeSet attrs, int defaultStyle)
: base(context, attrs, defaultStyle)
{
//Disable the scroll bar
HorizontalScrollBarEnabled = false;
//Make sure the tab strips fill the view
FillViewport = true;
this.SetBackgroundColor(Android.Graphics.Color.Rgb(0xE5, 0xE5, 0xE5)); //Gray color
mTitleOffset = (int)(TITLE_OFFSET_DIPS * Resources.DisplayMetrics.Density);
mTabStrip = new SlidingTabStrip(context);
this.AddView(mTabStrip, LayoutParams.MatchParent, LayoutParams.MatchParent);
}
public TabColorizer CustomTabColorizer
{
set { mTabStrip.CustomTabColorizer = value; }
}
public int[] SelectedIndicatorColor
{
set { mTabStrip.SelectedIndicatorColors = value; }
}
public int[] DividerColors
{
set { mTabStrip.DividerColors = value; }
}
public ViewPager.IOnPageChangeListener OnPageListener
{
set { mViewPagerPageChangeListener = value; }
}
public ViewPager ViewPager
{
set
{
mTabStrip.RemoveAllViews();
mViewPager = value;
if (value != null)
{
value.PageSelected += value_PageSelected;
value.PageScrollStateChanged += value_PageScrollStateChanged;
value.PageScrolled += value_PageScrolled;
PopulateTabStrip();
}
}
}
void value_PageScrolled(object sender, ViewPager.PageScrolledEventArgs e)
{
int tabCount = mTabStrip.ChildCount;
if ((tabCount == 0) || (e.Position < 0) || (e.Position >= tabCount))
{
//if any of these conditions apply, return, no need to scroll
return;
}
mTabStrip.OnViewPagerPageChanged(e.Position, e.PositionOffset);
View selectedTitle = mTabStrip.GetChildAt(e.Position);
int extraOffset = (selectedTitle != null ? (int)(e.Position * selectedTitle.Width) : 0);
ScrollToTab(e.Position, extraOffset);
if (mViewPagerPageChangeListener != null)
{
mViewPagerPageChangeListener.OnPageScrolled(e.Position, e.PositionOffset, e.PositionOffsetPixels);
}
}
void value_PageScrollStateChanged(object sender, ViewPager.PageScrollStateChangedEventArgs e)
{
mScrollState = e.State;
if (mViewPagerPageChangeListener != null)
{
mViewPagerPageChangeListener.OnPageScrollStateChanged(e.State);
}
}
void value_PageSelected(object sender, ViewPager.PageSelectedEventArgs e)
{
if (mScrollState == ViewPager.ScrollStateIdle)
{
mTabStrip.OnViewPagerPageChanged(e.Position, 0f);
ScrollToTab(e.Position, 0);
}
if (mViewPagerPageChangeListener != null)
{
mViewPagerPageChangeListener.OnPageSelected(e.Position);
}
}
private void PopulateTabStrip()
{
PagerAdapter adapter = mViewPager.Adapter;
for (int i = 0; i < adapter.Count; i++)
{
TextView tabView = CreateDefaultTabView(Context);
tabView.Text = ((SlidingTabsFragment.SamplePagerAdapter)adapter).GetHeaderTitle(i);
tabView.SetTextColor(Android.Graphics.Color.Black);
tabView.Tag = i;
tabView.Click += tabView_Click;
mTabStrip.AddView(tabView);
}
}
void tabView_Click(object sender, EventArgs e)
{
TextView clickTab = (TextView)sender;
int pageToScrollTo = (int)clickTab.Tag;
mViewPager.CurrentItem = pageToScrollTo;
}
private TextView CreateDefaultTabView(Android.Content.Context context)
{
TextView textView = new TextView(context);
textView.Gravity = GravityFlags.Center;
textView.SetTextSize(ComplexUnitType.Sp, TAB_VIEW_TEXT_SIZE_SP);
textView.Typeface = Android.Graphics.Typeface.DefaultBold;
if (Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Honeycomb)
{
TypedValue outValue = new TypedValue();
Context.Theme.ResolveAttribute(Android.Resource.Attribute.SelectableItemBackground, outValue, false);
textView.SetBackgroundResource(outValue.ResourceId);
}
if (Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.IceCreamSandwich)
{
textView.SetAllCaps(true);
}
int padding = (int)(TAB_VIEW_PADDING_DIPS * Resources.DisplayMetrics.Density);
textView.SetPadding(padding, padding, padding, padding);
return textView;
}
protected override void OnAttachedToWindow()
{
base.OnAttachedToWindow();
if (mViewPager != null)
{
ScrollToTab(mViewPager.CurrentItem, 0);
}
}
private void ScrollToTab(int tabIndex, int extraOffset)
{
int tabCount = mTabStrip.ChildCount;
if (tabCount == 0 || tabIndex < 0 || tabIndex >= tabCount)
{
//No need to go further, dont scroll
return;
}
View selectedChild = mTabStrip.GetChildAt(tabIndex);
if (selectedChild != null)
{
int scrollAmountX = selectedChild.Left + extraOffset;
if (tabIndex > 0 || extraOffset > 0)
{
scrollAmountX -= mTitleOffset;
}
this.ScrollTo(scrollAmountX, 0);
}
}
}
}
这是它的样子： Image
非常感谢任何帮助，谢谢！
答案 0 :(得分：4)
您应该使用DOMReady代替：
使用FragmentPagerAdapter方法创建片段并充气xml。
您的OnCreate应如下所示：
FragmentPagerAdapter然后在您的活动或片段中初始化viewpager。
public class MenuPagerAdapter : FragmentPagerAdapter
{
private string[] Titles;
private List<Android.Support.V4.App.Fragment> _fragments;
Android.Support.V4.App.FragmentManager _fragmentManager;
public MenuPagerAdapter(Android.Support.V4.App.FragmentManager fm, string[] titles)
: base(fm)
{
Titles = titles;
_fragments = new List<Android.Support.V4.App.Fragment>();
_fragments.Add(new HomeFragment());
_fragments.Add(new SurfboardKopenFragment());
_fragments.Add(new NieuwsbriefFragment());
_fragments.Add(new ContactFragment()); // and etc.
}
public override Android.Support.V4.App.Fragment GetItem(int position)
{
return _fragments[position];
}
public override ICharSequence GetPageTitleFormatted(int position)
{
return new Java.Lang.String(Titles[position]);
}
public override int Count
{
get { Titles.Length; } // amount of fragments you have = Amount of Tab titles.
}
public override int GetItemPosition(Java.Lang.Object objectValue)
{
return PositionNone;
}
public Android.Support.V4.App.Fragment GetFragment(int position)
{
return _fragments[position];
}
}
在您的片段或活动中实施 private MenuPagerAdapter adapter;
private CustomViewPager pager;
void InitAdapter()
{
string[] titles = new []
{
"Home",
"..."
};
pager = FindViewById<CustomViewPager>(Resource.Id.pager);
pager.EnableTouchEvents(true);
adapter = new MenuPagerAdapter(SupportFragmentManager, titles);
var pageMargin = (int)TypedValue.ApplyDimension(ComplexUnitType.Dip, 4, Resources.DisplayMetrics);
pager.OffscreenPageLimit = titles.Length;//amount of fragments you want to stay in memory(for faster tab change)
pager.PageMargin = pageMargin;
pager.AddOnPageChangeListener(this);
pager.Adapter = adapter;
pager.CurrentItem = 0;
}
：
Android.Support.V4.View.ViewPager.IOnPageChangeListener重要说明：
如果您坚持在片段中使用public void OnPageScrollStateChanged(int state)
{
}
public void OnPageScrolled(int position, float positionOffset, int positionOffsetPixels)
{
// Do anything you like when page scrolls
}
public void OnPageSelected(int position)
{ // Do anything you like when tab is clicked. Position is clicked Tab position.
switch (position)
{
case 0:
break;
case 1:
break;
case 2:
break;
case 3:
break;
case 4:
break;
case 5:
break;
default:
break;
}
}
，则应使用ChildFragmentManager adapter = new MenuPagerAdapter(SupportFragmentManager, this, pager);代替SupportFragmentManager。
重要建议：
完全删除viewpager并将所有内容从此处移至MainActivity。
编辑：由于代码中存在一些复制/粘贴错误，因此决定使用PagerSlidingTabStrip创建示例项目。玩得开心： PagerSlidingTabStrip-Sample